We report the case of a 45-year-old female referred to us with progressive shortness of breath and a huge left mediastinal mass. Computed tomography of the chest revealed a mass occupying the posterior mediastinum and extending from the apex caudally to the left hemidiaphragm. Further magnetic resonance imaging demonstrated tumor extension to the left interverteberal foramina of T5-T6 and T6-T7. Excision of the mass was performed through a left posterolateral thoracotomy. Histology confirmed a mediastinal ganglioneuroma. This is an unusual tumor with more than one extension in the spine. Ganglioneuromas are rare tumors of the peripheral nervous system. Most of these tumors are, however, retroperitoneal and are more common in children and young adults. Ganglioneuromas arise from neural crest cells. These tumors are mostly asymptomatic, but some may present with hypertension and flushing. Massive tumors can present with pressure symptoms.